Gradual deterioration of stored-water quality and actual danger of critical breakdown of the treatment technology supplying some 1.5 M inhabitants of the Prague-Agglomeration with drinking water are addressed by the conceited governmental action programme proposed in 1992 jointly by the Ministries of Environment and Agriculture of the Czech Republic. The programme is based on hitherto long-term extensive studies and includes additional research, investigation and monitoring works, design and implementation of abatement projects as well as policy, legislation and institutional activities.
Massive growth of phytoplankton biomass throughout the dam reservoir promoted by the unwanted luxurious supply of phosphorus and nitrogen compounds was traced both to point and non-point pollution sources in the watershed. While phosphorus was found to be primarily borne by communal point sources, nitrogen in the yearly amount of 2-3,000 t is mainly an indirect by-product of actual agricultural cropping systems. Long-term research has brought the evidence of complex microbial transformation, mineralization, nitrification and other processes involved in the nitrogen transport to the reservoir. To date other pollutants, e.g. chlorides, sulphates, heavy metals and organics have neither reached safety limits nor displayed excessive growing trends in the reservoir.